2009年9月，在泰国进行的一项由美国军方支持的医疗试验发现，某实验性疫苗能将感染艾滋病毒的风险大大降低。人类首次获得了具有一定免疫效果的艾滋病疫苗。

Challenges in the development of an HIV-1 vaccine

1) extensive viral clase and sequence diversity

2) early establishment of latent viral reservoirs

3) immune correlates of protection unclear

4) viral evasion of humoral and cellular immune responses.

5) antibody responses typically type-specific

6) no method exists to elicit broadly reactive neutralizing antibodies

7) attenuated viruses unsafe for human use

8) lack of small-animal model

9) little pharmaceutical interest